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Biomedical subjects

Javier Bermejo

Publications and source records attributed to Javier Bermejo.

33 records · Page 2Linked to original sources
PubMed2003

[Comparison of echocardiographic studies made with new portable devices to conventional studies].

OBJECTIVES: The latest development in echocardiography is the hand-held ultrasound device. Previous studies have shown that portable ultrasound devices detect major cardiovascular pathology better than the physical examination, but their diagnostic accuracy is still not known. The purpose of this study was to compare the results of examinations made with portable devices to those obtained with higher-scale platforms. PATIENTS AND METHOD: 211 consecutive unselected patients were included in the study. Patients were randomly studied with a portable device and a standard platform (considered the gold standard for comparison) by cardiologists experienced in echocardiography. Parameters of cardiac morphology and function, and valvular regurgitation were compared and analyzed using the McNemar paired test. Differences of more than one grade were considered major differences. RESULTS: The subjective assessment of the studies made with the portable device was significantly worse. The correlation between estimates of left ventricular function (differences not statistically significant) was adequate, but significant differences were detected in the evaluation of left atrial enlargement, left ventricular hypertrophy, aortic root enlargement, and mitral and tricuspid regurgitation. CONCLUSIONS: Hand-held cardiac ultrasound devices do not satisfy criteria for a complete echocardiographic study. They provide accurate information about ventricular function but fail to adequately measure cardiac chambers or assess valve function.

Adult↗
PubMed2003

[Image techniques for the evaluation and clinical decision making of patients with stroke].

The clinical relevance of cardiac embolism a potential cause of stroke is progressively increasing, mainly due to the recent progress in diagnostic imaging. In the present paper, we update and review the state of the art of the different etiologies currently accepted of a cardiac source of stroke. Furthermore, we review the clinical role of different image techniques, emphasizing the doubts and realities of each particular approximation.

Decision Making↗
PubMed2003

New techniques for the assessment of regional left ventricular wall motion.

The assessment of regional left ventricular (LV) function has been an important yet unresolved problem since the introduction of echocardiography as a diagnostic tool. Abnormal regional LV wall motion is an early finding in multiple cardiac pathologies and its diagnosis is of critical importance. In the last few years diagnostic procedures based on combined use of existing echocardiographic technologies were geared toward improving the accuracy of detection of baseline and/or induced regional wall motion abnormalities. One of the assumptions is that the combination of reduced LV wall thickening and reduced myocardial velocities can be used to accurately diagnose regional myocardial dysfunction. In this article we will discuss several new techniques for the quantification of regional LV function using Doppler echocardiography.

Aging↗
PubMed2002

[Safety and usefulness of transesophageal echocardiography in the acute phase of myocardial infarction].

INTRODUCTION AND OBJECTIVES: The usefulness and safety of transesophageal echocardiography have been assessed in other studies but there is no report in which these factors have been evaluated in the acute phase of myocardial infarction. Patients and method. Transesophageal echocardiography was performed 56 times in 55 patients in the first week after a myocardial infarction. RESULTS: The study was completed in 54 of 56 patients. The indications were a transthoracic acoustic window that did not provide an accurate diagnosis in 13 (23.2%), diagnosis of mechanical complications and severity assessment of mitral regurgitation in 35 (62.5%), exclusion of aortic dissection in 4 (7.1%), assessment of the severity of aortic stenosis in 1 (1.8%), exclusion of the presence of atrial thrombus in 1 (1.8%), evaluation of the left ventricular outflow tract gradient in 1 (1.8%), and evaluation of the presence of a left ventricular thrombus in 1 patient (1.8%). Two patients (3.6%) died while the study was being made, the first one 10 minutes after finishing the echocardiogram due to progression of a partial rupture of the papillary muscle and the second due to left ventricle free wall rupture. In both patients, the indication for transesophageal echography was the need for proper evaluation of a post-Acute Myocardial Infarction mechanical complication. CONCLUSIONS: Transesophageal echocardiography is a very useful technique for evaluating patients during the acute phase of myocardial infarction but further studies are needed to establish its safety in these patients.

Acute Disease↗
PubMed2002

Intramyocardial analysis of regional systolic and diastolic function in ischemic heart disease with Doppler tissue imaging: role of the different myocardial layers.

BACKGROUND: Preliminary experimental data have shown a nonuniform distribution of myocardial velocities (MVs) across the myocardial wall in normal conditions. However, after ischemic damage to the myocardium, a different pattern of reduction in the myocardial layers has been reported. The aim of this study is to analyze the spatial distribution of MVs and the resultant myocardial velocity gradients (MVGs) during the systolic and diastolic time periods. Doppler tissue imaging (DTI) in color M-mode was used to evaluate 3 different myocardial layers (endocardium, mesocardium, and epicardium) and their changes as a result of ischemia. METHODS: Thirty-two consecutive patients were studied with DTI color M-mode: 18 patients with a history of previous or ongoing myocardial infarction and 14 healthy subjects. Postprocessing of images was accomplished with proprietary software. MV and MVG values of all layers along both systolic and diastolic time were calculated. For temporal analysis, systole was subdivided in 3 equal periods. Early- and late-diastolic times were also identified. RESULTS: In ischemic patients, the mean MV and maximum MV throughout systole decreased significantly in the endocardium and mesocardium, whereas only slightly in the epicardium. The mean MVG was less in ischemic patients (0.66 +/- 0.11 vs 0.23 +/- 0.15, P <.03). Temporal analysis showed a decrease in the maximal MV and MVG in all layers over the 3 systolic periods. This decrease was the more consistent in mesocardium. In diastole, there was a decrease in maximal MV in all layers, being more pronounced in endocardium and mesocardium. Diastolic mean MVG was shown to be different between control and ischemic groups (-0.2 +/- 0.05 vs -0.10 +/- 0.04, P <.06). A significant decrease of the maximal MV in endocardium and mesocardium was reported in the temporal analysis during early diastole. No change was reported in the epicardium. The MVG value also showed a significant decrease (-2.69 +/- 0.29 vs -1.59 +/- 0.89, P <.02). In ischemic patients in late diastole, the maximum MV was increased in all layers of the myocardium, and this increase was observed mainly in the endocardium. An increase in the MVG (-0.78 +/- 0.18 vs -1.47 +/- 0.85, P = NS) was also reported during late diastole. CONCLUSION: There is a nonuniform distribution of velocities in the different myocardial layers under normal conditions. This distribution of velocities undergoes a significant change in patients with ischemic myocardial damage. Intramyocardial wall motion analysis could have clinical applications in both the early detection of ischemia and myocardial viability.

Adolescent↗
PubMed2002

In-vivo analysis of the instantaneous transvalvular pressure difference-flow relationship in aortic valve stenosis: implications of unsteady fluid-dynamics for the clinical assessment of disease severity.

BACKGROUND AND AIM OF THE STUDY: Because the hemodynamic basis of aortic valve area (AVA) has never been validated in vivo, several alternative indices have been proposed to quantify the severity of aortic stenosis (AS). This study was designed to assess the fluid-dynamics of aortic valve stenosis in order to clarify which index best accounts for disease severity. The diagnostic implications of reversed deltaP during ejection were also investigated. METHODS: Chronic valvular AS characterized by stiff leaflets without commissural fusion was created surgically in eight adult mongrel dogs; three additional animals were used as controls. At two-week intervals (three studies per dog), simultaneous micromanometer pressure and transit-time Q measurements were collected under different hemodynamic conditions. Instantaneous deltaP and Q signals were processed digitally and fitted to a modified form of the unsteady Bernoulli equation in which AS is characterized by effective valve area. RESULTS: An unsteady Bernoulli equation accurately predicted measured instantaneous AP values (R = 0.97+/-0.06), and a quadratic correlation was observed between instantaneously fitted and Gorlin-derived AVA. Additionally, deltaP < 0 mmHg during late ejection was observed in the majority of AS datasets, with a normalized time to deltaP reversal of 93+/-13% for AS animals versus 69+/-36% for controls (p <0.0005). Time to deltaP reversal inversely correlated with the Strouhal number (R = -0.77), and was responsible for an overestimation of mean systolic transvalvular deltaP and Q that resulted in a significant bias in the Gorlin method. Error was highest in moderate stenosis with low transvalvular output. CONCLUSION: Unsteady fluid-dynamics supports AVA over other measures of AS such as aortic valve resistance. However importantly, late-ejection reversal of deltaP precludes estimating the systolic ejection period from pressure tracings, and accounts for an additional source of error when AS is quantified invasively.

Animals↗
PubMed1999

Regional Left Ventricular Diastolic Dysfunction Evaluated by Pulsed-Tissue Doppler Echocardiography.

Pulsed-wave Doppler tissue imaging (DTI) allows the examination of regional wall motion at a very high temporal resolution and therefore constitutes an excellent technique for assessing diastolic motion of left ventricular walls. Regional relaxation has been well characterized in normal subjects using this technique, and physiological time intervals and motion wave profiles are described. In an experimental model of acute ischemia, local relaxation impairment was observed showing highly characteristic local diastolic abnormalities. Interestingly, these findings took place before any decrease in systolic motion was recordable. In a prospective clinical study, noninvasive regional DTI parameters were compared with coronary angiography to assess the feasibility and clinical value of the technique; the diagnostic accuracy is discussed in detail. Also, the association between regional diastolic parameters and global regional function as assessed by Doppler analysis of transmitral left ventricular filling flow was studied, stressing the impact of regional diastolic function on overall ventricular performance. Finally, the diagnostic role of pulsed-wave DTI on stress testing, identification of myocardial viability, and microvascular angina is reviewed.

Journal Article↗
PubMed1999

Stress Echocardiography in Aortic Stenosis: Insights into Valve Mechanics and Hemodynamics.

Stress interventions have been classically combined with cardiac catheterization recordings to understand the hemodynamic principles of valvular stenosis. Indices of aortic stenosis such as pressure gradient and valve area were based on simple hydraulic principles and have proved to be clinically useful for patient management during a number of decades. With the advent of Doppler echocardiography, these hemodynamic indices can be readily obtained noninvasively. Abundant evidence obtained using exercise and pharmacological stress echocardiography has demonstrated that the assumptions of classic hemodynamic models of aortic stenosis were wrong. Consequently, it is recognized that conventional indices may be misleading indicators of aortic stenosis significance in particular clinical situations. To improve diagnostic accuracy, several alternative hemodynamic models have been developed in the past few years, including valve resistance and left ventricular stroke work loss, among others. Nevertheless, these more-accurate indices should be obtainable noninvasively and need to demonstrate greater diagnostic and prognostic power than conventional indices; preliminary data suggest such superiority. Stress echocardiography is well established as the tool of choice for testing hypothesis and physical models of cardiac valve function. Although the final role of alternative indices is not yet well established, the new insights into valvular hemodynamics provided by this technique may change the clinical assessment of aortic stenosis.

Journal Article↗
PubMed1999

Regional Diastolic Function in Microvascular Angina Studied by Pulsed-Wave Doppler Tissue Imaging.

OBJECTIVES: Diastolic dysfunction is an early finding during myocardial ischemia. However, regional diastolic function has not been studied in patients with microvascular angina (MA). The purpose of this study was to assess the regional diastolic function in patients with MA through use of the new echocardiographic technique, pulsed-wave Doppler tissue imaging (DTI). METHODS: Regional diastolic function was studied by DTI in 81 myocardial segments of seven patients with MA and in 54 segments of six healthy control subjects. RESULTS: Myocardial segments in patients with MA had, in comparison with controls, an increased regional isovolumetric relaxation time (126 +/- 34 vs 99 +/- 34 msec, P < 0.0001), a higher e/a ratio (1.1 +/- 0.7 vs 0.8 +/- 0.3, P = 0.0048), and a lower peak velocity of the late diastolic wave a (6.9 +/- 2.9 vs 8.4 +/- 1.7 cm/msec, P = 0.0009). Moreover, peak velocity of systolic wave s was higher in patients with MA (5.8 +/- 1.4 vs 5.3 +/- 1.2 cm/msec, P = 0.0424). CONCLUSIONS: Patients with MA have an impaired regional diastolic function (an increased regional isovolumetric relaxation time and a lower a wave) and a higher velocity of the regional systolic wave s. These findings may have physiopathological implications.

Journal Article↗